mirror of
https://github.com/bol-van/zapret.git
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133 lines
3.0 KiB
C
133 lines
3.0 KiB
C
#define _GNU_SOURCE
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#include "protocol.h"
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#include "helpers.h"
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#include <string.h>
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#include <ctype.h>
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#include <arpa/inet.h>
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#include <string.h>
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const char *http_methods[] = { "GET /","POST /","HEAD /","OPTIONS /","PUT /","DELETE /","CONNECT /","TRACE /",NULL };
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bool IsHttp(const uint8_t *data, size_t len)
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{
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const char **method;
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size_t method_len;
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for (method = http_methods; *method; method++)
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{
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method_len = strlen(*method);
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if (method_len <= len && !memcmp(data, *method, method_len))
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return true;
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}
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return false;
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}
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bool HttpExtractHost(const uint8_t *data, size_t len, char *host, size_t len_host)
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{
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const uint8_t *p, *s, *e=data+len;
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p = (uint8_t*)strncasestr((char*)data, "\nHost:", len);
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if (!p) return false;
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p+=6;
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while(p<e && (*p==' ' || *p=='\t')) p++;
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s=p;
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while(s<e && (*s!='\r' && *s!='\n' && *s!=' ' && *s!='\t')) s++;
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if (s>p)
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{
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size_t slen = s-p;
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if (host && len_host)
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{
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if (slen>=len_host) slen=len_host-1;
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for(size_t i=0;i<slen;i++) host[i]=tolower(p[i]);
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host[slen]=0;
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}
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return true;
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}
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return false;
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}
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bool IsTLSClientHello(const uint8_t *data, size_t len)
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{
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return len>=6 && data[0]==0x16 && data[1]==0x03 && data[2]>=0x01 && data[2]<=0x03 && data[5]==0x01 && (ntohs(*(uint16_t*)(data+3))+5)<=len;
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}
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bool TLSFindExt(const uint8_t *data, size_t len, uint16_t type, const uint8_t **ext, size_t *len_ext)
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{
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// +0
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// u8 ContentType: Handshake
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// u16 Version: TLS1.0
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// u16 Length
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// +5
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// u8 HandshakeType: ClientHello
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// u24 Length
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// u16 Version
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// c[32] random
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// u8 SessionIDLength
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// <SessionID>
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// u16 CipherSuitesLength
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// <CipherSuites>
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// u8 CompressionMethodsLength
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// <CompressionMethods>
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// u16 ExtensionsLength
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size_t l,ll;
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l = 1+2+2+1+3+2+32;
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// SessionIDLength
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if (len<(l+1)) return false;
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ll = data[6]<<16 | data[7]<<8 | data[8]; // HandshakeProtocol length
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if (len<(ll+9)) return false;
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l += data[l]+1;
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// CipherSuitesLength
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if (len<(l+2)) return false;
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l += ntohs(*(uint16_t*)(data+l))+2;
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// CompressionMethodsLength
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if (len<(l+1)) return false;
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l += data[l]+1;
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// ExtensionsLength
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if (len<(l+2)) return false;
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data+=l; len-=l;
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l=ntohs(*(uint16_t*)data);
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data+=2; len-=2;
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if (l<len) return false;
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uint16_t ntype=htons(type);
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while(l>=4)
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{
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uint16_t etype=*(uint16_t*)data;
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size_t elen=ntohs(*(uint16_t*)(data+2));
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data+=4; l-=4;
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if (l<elen) break;
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if (etype==ntype)
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{
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if (ext && len_ext)
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{
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*ext = data;
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*len_ext = elen;
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}
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return true;
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}
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data+=elen; l-=elen;
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}
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return false;
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}
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bool TLSHelloExtractHost(const uint8_t *data, size_t len, char *host, size_t len_host)
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{
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const uint8_t *ext;
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size_t elen;
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if (!TLSFindExt(data,len,0,&ext,&elen)) return false;
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// u16 data+0 - name list length
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// u8 data+2 - server name type. 0=host_name
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// u16 data+3 - server name length
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if (elen<5 || ext[2]!=0) return false;
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size_t slen = ntohs(*(uint16_t*)(ext+3));
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ext+=5; elen-=5;
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if (slen<elen) return false;
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if (ext && len_host)
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{
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if (slen>=len_host) slen=len_host-1;
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for(size_t i=0;i<slen;i++) host[i]=tolower(ext[i]);
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host[slen]=0;
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}
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return true;
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}
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